The primary objectives of this clinical study are to evaluate the safety and tolerability of simultaneous administration of indinavir and rifabutin for 14 days; to evaluate the effect of simultaneous administration of rifabutin with indinavir for 14 days on the plasma pharmacokinetic profile of rifabutin; to evaluate the effect of staggered versus simultaneous administration of indinavir on the PK profile of rifabutin; and to evaluate the effect of simultaneous administration of rifabutin 150 mg and indinavir 1000 mg on the pharmacokinetics of indinavir. The secondary objective is to evaluate the effect of staggered vs. simultaneous administration on the PK profile of 25-desacetyl rifabutin.